Hydroxynaphthalenesulfonic acid refers to organic compounds with the formula . Several are precursors to azo dyes and to various aminonaphthalenesulfonic acids. They are colorless solids with high solubility in water.
In addition to these compounds, several dihydroxynaphthalenes, naphthalenedisulfonic acids, naphthalenetrisulfonic acids, hydroxynaphthalenedisulfonic acids, hydroxynaphthalenetrisulfonic acids, and aminonaphthalenesulfonic acids are valuable.